DESCRIPTION: The investigator proposes a model and means for studying hypoxia/ischemia protective interventions. Oxygen levels, phosphate metabolites and cerebral blood flow will be studied in experiments that are as parallel as the measurements allow. The problems in making the different measurements at the same time were handled well in the introduction to the revised application. This is a revised application proposing the use of NMR and EPR to probe metabolic parameters related to ischemic and hypoxic brain.